InternationalConstruction and engineering
Prefabricated bathrooms in innovative leightweight design
Quality starts with the construction
Two prefabricated bathrooms may look identical but be built very differently. Quality depends not only on the visible materials and final finish, but also to a large extent on the construction behind the tiles.
At Green Box, we have developed a carefully engineered lightweight construction in which material choices, waterproofing and technical details are carefully coordinated to ensure high quality and long-lasting durability.
Our bathrooms are built around an enclosed structure of hot-dip galvanised steel cassettes, with no organic materials on the exterior. Large-format Fermacell gypsum fibreboards are fully bonded to the steel cassettes, while floors and tiled walls are waterproofed using wet room sheet membranes before the tiles are installed.
This means, among other things, that tiles are never installed directly onto the steel structure. The different construction layers help protect the steel against moisture and reduce the risk of corrosion.
Below, you can learn more about the individual construction elements and the technical principles behind Green Box bathrooms.
The construction makes the difference.
More carefully engineered layers, fewer potential risk points.
Strong and stable steel construction
Green Box bathrooms are built around a lightweight construction of hot-dip galvanised steel cassettes, combining high strength and stability with low weight.
The closed steel structure is designed to withstand the stresses that bathrooms are exposed to during transport, installation and the construction phase. We also avoid using organic materials on the exterior of the structure that could be vulnerable to moisture.
With a standard weight of approximately 325 kg/m², Green Box bathrooms are well suited for traditional concrete construction, modular construction and various types of timber construction, including CLT.
The low weight provides great flexibility in the design phase and can help reduce the load on the building’s load-bearing structures. At the same time, the reduced material consumption can contribute to lowering the overall carbon footprint of the building project.
Floor construction with a low installation height
The floor construction in Green Box bathrooms consists of a steel frame with a reduced concrete layer. This allows for an installation height as low as 95 mm while maintaining the strength and stability of the structure.
The floor is cast on a laser-cut template, ensuring high precision with tolerances of ± 1 mm and the correct gradient towards the drain.
The low installation height makes it possible to reduce the thickness of the floor structure and thereby the overall building height. This can also help reduce material consumption and costs in the construction project.
Seamless wet room sheet membrane
At Green Box, we use wet room sheet membranes without joints on floors and tiled walls.
Unlike traditional liquid-applied membranes, where the thickness depends on the application, sheet membranes have a uniform thickness from the outset. This provides more reliable and controlled waterproofing and reduces the risk of moisture penetrating the underlying structure.
The adhesive used with the sheet membrane also helps prevent tiles from coming loose.
Long-lasting durability and greater protection
Wet room sheet membranes offer higher resistance to water pressure than traditional liquid-applied membranes. The combination of uniform thickness and installation without joints across individual surfaces creates a robust water barrier that helps protect the structure against moisture damage and supports the long-term durability of the bathrooms.
Quick and efficient installation with no drying time
Unlike liquid-applied membranes, sheet membranes do not require traditional drying time. Tiling can therefore begin shortly after the membrane has been installed. This makes the production process more efficient and reduces waiting time between individual work stages.
Less material waste
Using wet room sheet membranes allows for more precise control of material consumption. The uniform thickness reduces the risk of excessive material use during application, while the standardised process helps minimise material waste and keep material costs down.
Consistent and documented quality
The wet room sheet membrane is installed under controlled conditions at our factory in Denmark. The standardised process contributes to consistent workmanship and allows us to carry out quality assurance checks on every individual bathroom.
Through our digital quality assurance system and a unique QR code, you have access to documentation for each individual bathroom. This ensures traceability and provides confidence in the quality of each bathroom, both during construction and after handover.
Plasterboard ceilings with a refined finish
At Green Box, smooth plasterboard ceilings are standard. We only use full-size gypsum fibreboards. This means one surface = one board, with no joints that need to be glued or filled.
The ceiling is constructed using steel cassettes, onto which Fermacell gypsum fibreboards are fully bonded. This creates a smooth, robust surface with a refined finish.
The uniform ceiling surface complements the overall bathroom design, making plasterboard ceilings an ideal choice for a wide range of projects, including residential and hotel developments.
For safe integration of lighting, we install safety boxes around recessed spotlights, helping to maintain the ceiling’s airtightness and fire performance.
The ceiling can also be fitted with a discreet access hatch, providing easy access to installations without compromising the clean, uniform appearance.
Digitalisation and automation in production
At Green Box, we focus on digitalisation and automation to ensure an efficient production process with high precision and consistent quality.
The steel cassettes that form the framework of our bathrooms are punched and formed using a fully automated steel processing system. This ensures that each component is manufactured accurately and consistently.
Our bathrooms are manufactured on a production line, moving through different workstations. This means that the bathroom comes to the employee, rather than the other way around. This production method enables standardised workflows, efficient use of resources and continuous quality control.
We continuously develop and optimise our production processes, including through increased automation and the use of robotics.
Plumbing installations
How we carry out plumbing installations
The plumbing installations in Green Box bathrooms use PEX pipes, which are insulated up to the connection boxes. All fittings are made of gunmetal.
To ensure that the installations are watertight, all pipework is pressure-tested using electronic pressure-testing equipment. The results are documented in a quality report, which can be accessed via the unique QR code on each bathroom.
Drainage pipes can be routed to the service shaft within the walls. This helps keep the floor construction’s installation height low and provides flexibility during the technical design phase.
Fire and sound requirements
Documented fire and acoustic performance
Green Box bathrooms have been tested and third-party approved by the Danish Institute of Fire and Security Technology (DBI) for use as partitions between apartments, meeting requirements for both fire resistance and sound insulation.
When two bathrooms are positioned against each other, the construction can achieve a fire resistance rating of EI60 and meet sound insulation requirements of 55 dB.
We are happy to provide relevant documentation on request.
Strong packaging
Protection against the elements
Green Box bathrooms are designed to withstand the stresses of transport and storage in the open shell structure. The closed steel structure helps protect against water penetration, while a strong, UV-resistant shrink film protects the bathrooms from the elements.
The packaging allows the bathrooms to be stored in the open shell structure for up to six months, provided it remains intact. This offers great flexibility during construction, as installation can be scheduled to suit the progress of the building project.
CONTACT US
Your supplier of prefabricated bathrooms
WE ARE READY TO ADVISE YOU
Have questions or need guidance? Our team is ready to assist you.
As specialists in prefabricated bathrooms, we provide expert advice to help you identify and develop the optimal bathroom solution for your project.
Get in touch – we look forward to hearing from you.